Popular airlines from Los Angeles - Ontario Intl. Airport (ONT) to Seattle-Tacoma International Airport (SEA)
Alaska AirlinesAlaska Airlines
DeltaDelta
UnitedUnited
Frontier AirlinesFrontier Airlines
Southwest AirlinesSouthwest Airlines
American AirlinesAmerican Airlines
Hawaiian AirlinesHawaiian Airlines
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Cheap Flights from Ontario to Seattle (ONT-SEA)
Prices were available within the past 7 days and start at $49 for one-way flights and $98 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.
Frequently asked questions
Travel information
Travel information
Origin airport | Los Angeles - Ontario Intl. |
Destination airport | Seattle - Tacoma Intl. |
Airlines serving | Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, Southwest Airlines, United |
Roundtrip price | $98 |
Distance | 956 mi |
Book with confidence
Book with confidence
The cheapest times to fly from Ontario to Seattle
On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Ontario to Seattle are during the month of June. You can find some of the cheapest flights from Ontario to Seattle with Expedia's search tool and vast selection of airlines.
The best time to book a flight from Ontario to Seattle
Sunday is one of the best days to book for cheap flights from Ontario to Seattle: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.
How to find cheap round-trip tickets from Ontario to Seattle
Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Ontario to Seattle in 2025. You can also book with separate airlines for your outbound and return journeys, from $49 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.
Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Ontario to Seattle flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.
You could also save big by booking one of Expedia's vacation packages. Bundling together your Ontario to Seattle airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.
*Terms apply.
Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.
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Flights
- China Airlines Ontario (ONT) to Manila (MNL) flights
- Alaska Airlines Ontario (ONT) to Portland (PDX) flights
- Alaska Airlines Minneapolis (MSP) to Seattle (SEA) flights
- Alaska Airlines Houston (IAH) to Seattle (SEA) flights
- Alaska Airlines Chicago (ORD) to Seattle (SEA) flights
- Alaska Airlines Denver (DEN) to Seattle (SEA) flights
- Alaska Airlines Dallas (DAL) to Seattle (SEA) flights
- Alaska Airlines Boston (BOS) to Seattle (SEA) flights
- Alaska Airlines San Diego (SAN) to Seattle (SEA) flights
- Alaska Airlines Newark Liberty Intl. Airport (EWR) to Seattle (SEA) flights
- Alaska Airlines New York (JFK) to Seattle (SEA) flights
- Alaska Airlines Phoenix (PHX) to Seattle (SEA) flights
- Frontier Airlines Ontario (ONT) to Houston (IAH) flights
- Volaris Ontario (ONT) to Guadalajara (GDL) flights
- Delta Ontario (ONT) to Salt Lake City (SLC) flights
- American Airlines Ontario (ONT) to New York (JFK) flights
- American Airlines Ontario (ONT) to Newark Liberty Intl. Airport (EWR) flights
- Alaska Airlines Ontario (ONT) to Honolulu (HNL) flights
- Frontier Airlines Ontario (ONT) to Denver (DEN) flights
- American Airlines Ontario (ONT) to Phoenix (PHX) flights
- Flights from Chicago (ORD) to Los Angeles (LAX)
- Flights from New York (NYC) to Los Angeles (LAX)
- Flights from San Francisco (SFO) to Los Angeles (LAX)
- Flights from Dallas (DFW) to Los Angeles (LAX)
- Flights from Seattle (SEA) to Los Angeles (LAX)
- Flights from Ontario (ONT) to Manila (MNL)
- Flights from Los Angeles (LAX) to Manila (MNL)
- Flights from Ontario (ONT) to Portland (PDX)
- Flights from Los Angeles (LAX) to Seattle (SEA)
- Flights from Newark Liberty Intl. Airport (EWR) to Seattle (SEA)
- Flights from Houston (IAH) to Seattle (SEA)
- Flights from New York (JFK) to Seattle (SEA)
- Flights from Denver (DEN) to Seattle (SEA)
- Flights from Baltimore (BWI) to Seattle (SEA)
- Flights from Dallas (DAL) to Seattle (SEA)
- Flights from Boston (BOS) to Seattle (SEA)
- Flights from Phoenix (PHX) to Seattle (SEA)
- Flights from San Diego (SAN) to Seattle (SEA)
- Flights from Minneapolis (MSP) to Seattle (SEA)
- Flights from Chicago (ORD) to Seattle (SEA)
- Flights from Dallas (DFW) to Seattle (SEA)
- Flights from Ontario (ONT) to Houston (IAH)
- Flights from Ontario (ONT) to Guadalajara (GDL)
- Flights from Ontario (ONT) to Dallas (DFW)
- Flights from Ontario (ONT) to Salt Lake City (SLC)
- Flights from Boston (BOS) to Miami (MIA)
- Flights from Ontario (ONT) to New York (JFK)
- Flights from San Francisco (SFO) to New York (JFK)
- Flights from Ontario (ONT) to Dallas (DAL)
- Flights from Los Angeles (LAX) to Seoul (ICN)
- Flights from Portland (PDX) to Las Vegas (LAS)
- Flights from Dallas (DFW) to Las Vegas (LAS)
- Flights from Atlanta (ATL) to Las Vegas (LAS)
- Flights from Chicago (ORD) to Las Vegas (LAS)
- Flights from Houston (IAH) to Las Vegas (LAS)
- Flights from New York (NYC) to Las Vegas (LAS)
- Flights from Los Angeles (LAX) to Las Vegas (LAS)
- Flights from Detroit (DTW) to Las Vegas (LAS)
- Flights from San Francisco (SFO) to Las Vegas (LAS)
- Flights from Seattle (SEA) to Las Vegas (LAS)
- Flights from Boston (BOS) to Orlando (MCO)
- Flights from Philadelphia (PHL) to Orlando (MCO)
- Flights from Los Angeles (LAX) to Chicago (ORD)
- Flights from Los Angeles (LAX) to New York (NYC)
- Flights from Atlanta (ATL) to New York (NYC)
- Flights from Dallas (DFW) to New York (NYC)
- Flights from Ontario (ONT) to Newark Liberty Intl. Airport (EWR)
- Flights from Los Angeles (LAX) to Honolulu (HNL)
- Flights from Ontario (ONT) to Honolulu (HNL)
- Flights from Los Angeles (LAX) to Tokyo (NRT)
- Flights from Los Angeles (LAX) to San Francisco (SFO)
- Flights from Ontario (ONT) to Denver (DEN)
- Flights from Ontario (ONT) to Phoenix (PHX)
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